Wide angle zoom lens

ABSTRACT

This specification discloses a zoom lens which comprises, in succession from the object side, a divergent lens group and a convergent lens group and whose magnification is changed by relative movement of the two groups. The divergent lens group comprises, in succession from the object side, three continuous negative meniscus lenses having their respective convex surfaces facing the object side and a positive lens having its surface of sharper curvature facing the object side. The convergent lens group comprises, in succession from the object side, a single biconvex positive lens, a meniscus lens comprising a doublet and having its convex surface facing the object side, a positive lens, a negative lens and two continuous positive lenses. The zoom lens satisfies predetermined conditions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a wide angle zoom lens which covers an angleof view of 90° or greater and which is compact and in which variousaberrations have been well corrected.

2. Description of the Prior Art

In zoom lenses covering a wide angle of view and comprising a forwardgroup which is a divergent lens group and a rearward group which is aconvergent lens group, it has been a matter of great concern in recentyears to correct various aberrations while making the lens compact.Generally, however, a zoom lens, as compared with lenses having acorresponding fixed focal length, has a great full length due to theneed to secure a space available for the lens groups to move and theincreased number of lens components, and the lens system in apt tobecome bulky. Moreover, the full length of a so-called two-group zoomlens like the zoom lens of the present invention comprising a forwardgroup which is a divergent lens group and a rearward group which is aconvergent lens group is greater at the wide angle side and therefore,the lens system becomes remarkably bulky. Particularly, the diameter ofa filter mounted at a location in the lens system which is most adjacentto the object side has been considerably great in order to cover a wideangle of view, and reducing the diameter of such filter has been a greattask for making the entire lens system compact. A wide angle zoom lenshaving an angle of view exceeding 90° is disclosed in Japanese Laid-openPatent Application No. 135658/1978 (U.S. Pat. No. 4,196,968), but thiszoom lens is relatively bulky.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate the above-noteddisadvantages and to provide a zoom lens which covers up to anultra-wide angle of view and which is compact in size and in whichvarious aberrations have been well corrected.

The invention will become fully apparent from the following detaileddescription thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2 and 3 are cross-sectional views of the lenses according to afirst, a second and a third embodiments of the present invention.

FIGS. 4A-4C, 5A-5C and 6A-6C illustrate the spherical aberration,astigmatism and distortion in the respective embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention consists in a zoom lens which comprises, insuccession from the object side, a divergent lens group A and aconvergent lens group B and whose magnification in changed by relativemovement of the two groups and wherein the divergent lens group Acomprises four lenses, i.e., in succession from the object side, threecontinuous negative meniscus lenses L₁, L₂, L₃ haiving their respectiveconvex surfaces facing the object side and a positive lens L₄ having itssurface of sharper curvature facing the object side and the convergentlens group B comprises, in succession from the object side, a singlebeconvex positive lens L₅, a meniscus lens L₆ comprising a doublet andhaving its convex surface facing the object side, a posiitve lens L₇, anegative lens L₈ and two continuous positive lenses L₉, L₁₀, the zoomlens satisfying the following conditions:

(I) r₁ >3.4f_(W)

(II) 0.9|f_(A) |<|f₁₁ |<1.3|f_(A) | (f₁₁ <0,f_(A) <0)

(III) 0.9f_(W) >d₁₁ +d₁₂ +d₁₄ +d₁₅ >0.6f_(W)

(IV) 1.6f_(W) >|r₁₂ |>0.8f_(W) (r₁₂ <0)

where f_(A) represents the focal length of the divergent lens group A,f₁₁ represents the focal length of the negative meniscus lens L₁ whichis most adjacent to the object side, r represents the curvature radii ofthe lens surfaces, d represents the thicknesses of the lenses and theair spaces between the lenses, the subscripts represent the order fromthe object side, and f_(W) represents the focal length of the entiresystem at the wide angle end.

Conditions (I) and (II) are for intensifying the refractive powers ofthe first surface adjacent to the object side and the foremost lensadjacent to the object side for off-axial light rays to thereby reducethe diameter of a filter mounted at a location in the lens system whichis most adjacent to the object side and for keeping the principal pointposition of the divergent lens group at an optimal position. Light raysincident parallel to the optical axis pass through the portion of thenegative meniscus lens L₁, which is near the optical axis and therefore,even if the refractive power for off-axial light rays is intensified inthe negative meniscus lens L₁, it will not so much adversely affectspherical aberration and will not bring about a remarkable increase inthe duty of correction for the spherical aberration in the rearwardgroup. If condition (I) is departed from, the refractive power of thefirst surface for oblique light rays will become weak and result in anincreased diameter of the filter. When the upper limit of condition (II)is exceeded, the refractive power of the negative meniscus lens L₁ foroblique light rays will become weak while, at the same time, theprincipal point position of the divergent lens group A will move towardthe image side and therefore, the divergent lens group A will relativelymove toward the object side and the entrance pupil position will becomedistant and thus, the diameter of the forward lens and of the filterwill be increased. When the lower limit of condition (II) is exceeded,the principal point position of the divergent lens group A will move toomuch toward the object side and the air space between the divergent lensgroup A and the covergent lens group B will become too small tosufficiently secure a space available for the lens groups to move.

Condition (III) is concerned with the sum of the center thicknesses ofthe meniscus lens L₆ having its convex surface facing the object sideand the positive lens L₇, in the rearward group, and it is a conditionfor increasing the length of the light path of the convergent lens groupwithout increasing the diameter of the filter, thereby alleviating theduty of aberration correction and well correcting the off-axialaberrations which are liable to occur with the compaction of theforemost lens. The meniscus lens L₆ and the positive lens L₇ aresituated more adjacent to the image side than the diaphragm andtherefore, even if the length of the light path in this portion isincreased, it will not adversely affect the diameter of the filter atall. Also, by increasing the length of the light path from d₁₁ to d₁₅,the height of the oblique . light ray in the negative lens L₈ may beincreased to increase the effect of correction of distortion andastigmatism by the negative lens L₈. If the upper limit of condition(III) is exceeded, the diameter of the lens which is most adjacent tothe image side will become great and therefore, it will become difficultto secure the edge thickness and, if the lower limit of condition (III)is exceeded, astigmatism and distortion will occur. The air space d₁₃between the meniscus lens L₆ and the positive lens L₇ is requisite forthe correction of astigmatism, etc., and in order to make condition(III) more effective, it is desirable that d₁₃ <0.1f_(W).

Condition (IV) is concerned with the cemented surface of the meniscuslens L₆ having its convex surface facing the object side, in therearward group, and it is a condition for correcting the chromaticaberration of spherical aberration and the chromatic aberration ofastigmatism. In a zoom lens covering up to an ultra-wide angle like thezoom lens of the present invention, particularly the meridional imageplane of g-line tends to be remarkably curved in the positive direction,and by providing, for the correction of this, a cemented surface in aportion wherein light rays incident parallel to the optical axis passthrough a position farther from the optical axis, there may be providedthe effect of correcting the chromatic aberration of sphericalaberration at the same time. Since the cemented surface lies near thediaphragm, the adverse effect upon chromatic difference of magnificationhardly occurs. If the upper limit of condition (IV) is exceeded, thespherical aberration of g-line will be under and the back focal lengthwill be short because the refractive indices n₆ and n₇ of the positivelens and the negative lens joined together by this cemented surface aren₆ <n₇. If the lower limit of condition (IV) is exceeded, the chromaticaberrations of spherical aberration and astigmatism will occurremarkable.

The embodiment of the present invention as described above, when used asthe lens system for a 35mm single lens reflex camera, has a focal lengthof 21.5mm-34.5mm and covers an ultra-wide angle of view amounting to 90°and yet has a considerable zoom ratio and a maximum brightness of F3.7and, even if a filter having a diameter of 48mm is mounted at a locationwhich is most adjacent to the object side, such embodiment can be usedwithout being kicked over the entire zooming range and is very compact.

The lens constructions according to a first, a second and a thirdembodiment of the present invention are shown in FIGS. 1, 2 and 3,respectively. The first and the second embodiment are substantiallysimilar in construction, but the third embodiment is one in which thecemented surface of the positive lens L₇ in the rearward group iseliminated, and even such construction has a sufficient performance forpractical use. The various aberrations in the shortest, the intermediateand the longest focal length condition of the respective embodiments areillustrated in FIGS. 4A-4C, 5A-5C and 6A-6C, respectively.

Numerical data of the respective embodiments will be shown below. In thetables below, r represents the curvature radius of each lens surface, drepresents the center thicknesses and the air spaces of the lenses, ndand νd represent the refractive index and the Abbe number, respectively,of each lens, and the subscripts represent the order of these from theobject side. The constant of the non-spherical surface is also shown.

    __________________________________________________________________________    First Embodiment                                                              Total focal length of the entire system f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 84.839 d.sub.1                                                                         = 2.4   nd.sub.1                                                                         = 1.79668                                                                           νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 22.425 d.sub.2                                                                         = 4.8                                                            r.sub.3                                                                         = 89.55  d.sub.3                                                                         = 2.0   nd.sub.2                                                                         =1.79668                                                                            νd.sub.2                                                                      = 45.4                                   L.sub.2                                                                           r.sub.4                                                                         = 29.42  d.sub.4                                                                         =4.0                                                             r.sub.5                                                                         = 72.95  d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 42.56  d.sub.6                                                                         =6.0                                                             r.sub.7                                                                         = 43.6   d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = -3230  d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 61.32  d.sub.9                                                                         =  1.8  nd.sub.5                                                                         = 1.62374                                                                           νd.sub.5                                                                      = 47                                     L.sub.5                                                                           r.sub.10                                                                        = -80.084                                                                              d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 31.73  d.sub.11                                                                        = 4.5   nd.sub.6                                                                         = 1.6223                                                                            νd.sub.6                                                                      = 53.1                                   L.sub.6                                                                           r.sub.12                                                                        = -22.088                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub.13                                                                        = 40.721 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 24.05  d.sub.14                                                                        = 3.0   nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sub.7                                                                           r.sub.15                                                                        = 14.01  d.sub.15                                                                        = 6.5   nd.sub.9                                                                         = 1.54814                                                                           νd.sub.9                                                                      = 45.9                                       r.sub.16                                                                        = -55.266                                                                              d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -41.17 d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 24.62  d.sub.18                                                                        = 2.0                                                            r.sub.19                                                                        = -330.2 d.sub.19                                                                        = 3.8   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     = 56.5                                   L.sub.9                                                                           r.sub.20                                                                        = -20.9  d.sub.20                                                                        = 0.4                                                            r.sub.21                                                                        = -1262.13                                                                             d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.5168                                                                            νd.sub.12                                                                     = 64.2                                   L.sub.10                                                                          r.sub.22                                                                        = -33.667                                                               __________________________________________________________________________             l = 22.504 ˜ 0.5                                                        First surface (r.sub.1) non-spherical                                         K = 1, C.sub.2 = 0                                                            C.sub.4 = 0.6226 × 10.sup.-5 C.sub.6 = -0.3539 ×                  10.sup.-8                                                                     C.sub.8 = 0.2546 × 10.sup.-11 C.sub.10 = -0.3371 ×                10.sup.-16                                                                    f.sub.11 =-38.93 = 1.124fΛ                                    __________________________________________________________________________    Second Embodiment                                                             Total focal length of the entire system f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 87.25  d.sub.1                                                                         = 2.4   nd.sub.1                                                                          = 1.79668                                                                          νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 20.945 d.sub.2                                                                         = 4.35                                                           r.sub.3                                                                         = 33.125 d.sub.3                                                                         = 2.0   nd.sub.2                                                                         = 1.50137                                                                           νd.sub.2                                                                      = 56.5                                   L.sub.2                                                                           r.sub.4                                                                         = 21.95  d.sub.4                                                                         = 4.0                                                            r.sub.5                                                                         = 67.2   d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 27.96  d.sub.6                                                                         = 6.0                                                            r.sub.7                                                                         = 37.074 d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = 677.009                                                                              d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 64.66  d.sub.9                                                                         = 1.8   nd.sub.5                                                                         = 1.67003                                                                           νd.sub.5                                                                      = 47.2                                   L.sub.5                                                                           r.sub.10                                                                        = -78.003                                                                              d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 29.692 d.sub.11                                                                        =  4.497                                                                              nd.sub.6                                                                         = 1.6223                                                                            νd.sub.6                                                                      = 53.1                                   L.sub.6                                                                           r.sub.12                                                                        = -22.088                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub.13                                                                        = 33.203 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 24.71  d.sub.14                                                                        = 3.0   nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sub.7                                                                           r.sub.15                                                                        = 14.01  d.sub.15                                                                        = 6.5   nd.sub.9                                                                         = 1.54814                                                                           νd.sub.9                                                                      = 45.9                                       r.sub.16                                                                        = -46.087                                                                              d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -34.63 d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 27.53  d.sub.18                                                                        = 2.0                                                            r.sub.19                                                                        = -179.709                                                                             d.sub.19                                                                        = 3.8   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     = 56.5                                   L.sub.9                                                                           r.sub.20                                                                        = -19.92 d.sub.20                                                                        = 0.4                                                            r.sub. 21                                                                       = -1000.00                                                                             d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.51835                                                                           νd.sub.12                                                                     = 60.3                                   L.sub.10                                                                          r.sub.22                                                                        = -30.653                                                               __________________________________________________________________________             l = 22.517 ˜ 0.513                                                      Third surface (r.sub.3) non-spherical                                         K = 1, C.sub.2 = 0                                                            C.sub.4 = 0.1986 × 10.sup.-4 C.sub.6 = 0.1822 ×                   10.sup.-7                                                                     C.sub.8 = 0.1956 × 10.sup.-10 C.sub.10 = 0.216 ×                  10.sup.-12                                                                    f.sub.11 = -35.16 = 1.006fΛ                                   __________________________________________________________________________    Third Embodiment                                                              Total focal length of the entire sustem f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 97.4   d.sub.1                                                                         = 2.4   nd.sub.1                                                                         = 1.79668                                                                           νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 23     d.sub.2                                                                         = 4.77                                                           r.sub.3                                                                         = 88     d.sub.3                                                                         = 2.0   nd.sub.2                                                                         =  1.79668                                                                          νd.sub.2                                                                      = 45.4                                   L.sub.2                                                                           r.sub.4                                                                         = 29.92  d.sub.4                                                                         = 4.0                                                            r.sub.5                                                                         = 75.6   d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 42.07  d.sub.6                                                                         = 6.15                                                           r.sub.7                                                                         = 44.887 d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = -847.428                                                                             d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 69.2   d.sub.9                                                                         = 1.8   nd.sub.5                                                                         = 1.62374                                                                           νd.sub.5                                                                      = 47                                     L.sub.5                                                                           r.sub.10                                                                        = -92.85 d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 32.09  d.sub.11                                                                        = 4.5   nd.sub.6                                                                         = 1.62374                                                                           νd.sub.6                                                                      = 47                                     L.sub.6                                                                           r.sub.12                                                                        = -26.167                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub. 13                                                                       = 49.053 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 22.072 d.sub.14                                                                        = 8.532 nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sub.7                                                                           r.sub.16                                                                        = -93.3  d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -40.965                                                                              d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 22.941 d.sub.18                                                                        = 2.0                                                            r.sub.19                                                                        = -4438.92                                                                             d.sub.19                                                                        = 4.0   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     = 56.5                                   L.sub.9                                                                           r.sub.20                                                                        = -19.604                                                                              d.sub.20                                                                        = 0.4                                                            r.sub.21                                                                        = 13256.965                                                                            d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.51823                                                                           νd.sub.12                                                                     = 59                                     L.sub.10                                                                          r.sub.22                                                                        = -39.89                                                                __________________________________________________________________________             l = 22.582 ˜ 0.6                                                        First surface (r.sub.1) non-spherical                                         K = 1, C.sub.2 = 0                                                            C.sub.4 = 0.6062 × 10.sup.-5 C.sub.6 = -0.3366 ×                  10.sup.-8                                                                     C.sub.8 = 0.2327 × 10.sup.-11 C.sub.10 = -0.4809 ×                10.sup.-16                                                                    f.sub.11 = -38.34 = 1.097fΛ                                   __________________________________________________________________________

I claim:
 1. A zoom lens which comprises, in succession from the objectside, a divergent lens group (A) and a convergent lens group (B) andwhose magnification is changed by relative movement of the two groupsand wherein the divergent lens group (A) comprises four lenses, i.e., insuccession from the object side, three continuous negative meniscuslenses (L₁, L₂, L₃) having their respective convex surfaces facing theobject side and a positive lens (L₄) having its surface of sharpercurvature facing the object side and the convergent lens group (B)comprises, in succession from the object side, a single biconvexpositive lens (L₅), a meniscus lens (L₆) comprising a doublet and havingits convex surface facing the object side, a positive lens (L₇), anegative lens (L₈) and two continuous positive lenses (L₉, L₁₀), thezoom lens satisfying the following conditions:(I) r₁ >3.4f_(W) (II)0.9|f_(A) |<|f₁₁ |<1.3|f_(A) | (f₁₁ <0,f_(A) <0) (III) 0.9f_(W) >d₁₁+d₁₂ +d₁₄ +d₁₅ >0.6f_(W) (IV) 1.6f_(W) >|r₁₂ |>0.8f_(W) (r₁₂ <0)wheref_(A) represents the focal length of the divergent lens group (A), f₁₁represents the focal length of the negative meniscus lens (L₁) which ismost adjacent to the object side, r represents the curvature radii ofthe lens surfaces, d represents the thicknesses of the lenses and theair spaces between the lenses, the subscripts represent the order fromthe object side, and f_(W) represents the focal length of the entiresystem at the wide angle end.
 2. A zoom lens according to claim 1,wherein numerical data are as follows:

    __________________________________________________________________________    First Embodiment                                                              Total focal length of the entire system f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 84.839 d.sub.1                                                                         = 2.4   nd.sub.1                                                                         = 1.79668                                                                           νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 22.425 d.sub.2                                                                         = 4.8                                                            r.sub.3                                                                         = 89.55  d.sub.3                                                                         = 2.0   nd.sub.2                                                                         = 1.79668                                                                           νd.sub.2                                                                      = 45.4                                   L.sub.2                                                                           r.sub.4                                                                         = 29.42  d.sub.4                                                                         = 4.0                                                            r.sub.5                                                                         = 72.95  d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 42.56  d.sub.6                                                                         = 6.0                                                            r.sub.7                                                                         = 43.6   d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = -3230  d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 61.32  d.sub. 9                                                                        = 1.8   nd.sub.5                                                                         = 1.62374                                                                           νd.sub.5                                                                      = 47                                     L.sub.5                                                                           r.sub.10                                                                        = -80.084                                                                              d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 31.73  d.sub.11                                                                        = 4.5   nd.sub.6                                                                         = 1.6223                                                                            νd.sub.6                                                                      = 53.1                                   L.sub.6                                                                           r.sub.12                                                                        = -22.088                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub.13                                                                        = 40.721 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 24.05  d.sub.14                                                                        = 3.0   nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sup.7                                                                           r.sub.15                                                                        = 14.01  d.sub.15                                                                        = 6.5   nd.sub.9                                                                         = 1.54814                                                                           νd.sub.9                                                                      = 45.9                                       r.sub.16                                                                        = -55.266                                                                              d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -41.17 d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 24.62  d.sub.18                                                                        = 2.0    24.62                                                                           d.sub.18                                                                            = 2.0                                           r.sub.19                                                                        = -330.2 d.sub.19                                                                        = 3.8   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     = 56.5                                   L.sub.9                                                                           r.sub.20                                                                        = -20.9  d.sub.20                                                                        = 0.4                                                            r.sub.21                                                                        = -1262.13                                                                             d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.5168                                                                            νd.sub.12                                                                     = 64.2                                   L.sub.10                                                                          r.sub.22                                                                        = -33.67                                                                __________________________________________________________________________             l = 22.504 ˜ 0.5                                                        First surface (r.sub.1) non-spherical                                         K = 1, C.sub.2  = 0                                                           C.sub.4 = 0.6226 × 10.sup.-5 C.sub.6 = -0.3539 ×                  10.sup.-8                                                                     C.sub.8 = 0.2546 × 10.sup.-11 C.sub.10 = -0.3371 ×                10.sup.-16                                                                    f.sub.11 = -38.93 = 1.124fΛ                                   __________________________________________________________________________


3. A zoom lens according to claim 1, wherein numerical data are asfollows:

    __________________________________________________________________________    Second Embodiment                                                             Total focal length of the entire system f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 87.25  d.sub.1                                                                         = 2.4   nd.sub.1                                                                         = 1.79668                                                                           νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 20.945 d.sub.2                                                                         = 4.35                                                           r.sub.3                                                                         = 33.125 d.sub.3                                                                         = 2.0   nd.sub.2                                                                         = 1.50137                                                                           νd.sub.2                                                                      = 56.5                                   L.sub.2                                                                           r.sub.4                                                                         = 21.95  d.sub.4                                                                         = 4.0                                                            r.sub.5                                                                         = 67.2   d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 27.96  d.sub.6                                                                         = 6.0                                                            r.sub.7                                                                         = 37.074 d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = 677.009                                                                              d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 64.66  d.sub. 9                                                                        = 1.8   nd.sub.5                                                                         = 1.67003                                                                           νd.sub.5                                                                      = 47.2                                   L.sub.5                                                                           r.sub.10                                                                        = -78.003                                                                              d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 29.692 d.sub.11                                                                        = 4.497 nd.sub.6                                                                         = 1.6223                                                                            νd.sub.6                                                                      = 53.1                                   L.sub.6                                                                           r.sub.12                                                                        = -22.088                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub.13                                                                        = 33.203 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 24.71  d.sub.14                                                                        = 3.0   nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sub.7                                                                           r.sub.15 =                                                                      14.01                                                                           d.sub.15                                                                             = 6.5                                                                           nd.sub.9                                                                              = 1.54814                                                                        νd.sub.9                                                                         = 45.9                                          r.sub.16                                                                        = -46.087                                                                              d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -34.63 d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 27.53  d.sub.18                                                                        = 2.0                                                            r.sub.19                                                                        = -179.709                                                                             d.sub.19                                                                        = 3.8   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     =  56.5                                  L.sub.9                                                                           r.sub.20                                                                        = -19.92 d.sub.20                                                                        = 0.4                                                            r.sub.21                                                                        = -1000.00                                                                             d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.51835                                                                           νd.sub.12                                                                     = 60.3                                   L.sub.10                                                                          r.sub.22                                                                        = -30.653                                                               __________________________________________________________________________             l = 22.517 ˜ 0.513                                                      Third surface (r.sub.3) non-spherical                                         K = 1, C.sub.2 = 0                                                            C.sub.4 = 0.1986 × 10.sup.-4 C.sub.6 = 0.1822 ×                   10.sup.-7                                                                     C.sub.8 = 0.1956 × 10.sup.-10 C.sub.10 = 0.216 ×                  10.sup.-12                                                                    f.sub.11 = -35.16 = 1.006fΛ                                   __________________________________________________________________________


4. A zoom lens according to claim 1, wherein numerical data are asfollows:

    __________________________________________________________________________    Third Embodiment                                                              Total focal length of the entire system f = 21.5 ˜ 34.5                 __________________________________________________________________________        r.sub.1                                                                         = 97.4   d.sub.1                                                                         = 2.4   nd.sub.1                                                                         = 1.79668                                                                           νd.sub.1                                                                      = 45.4                                   L.sub.1                                                                           r.sub.2                                                                         = 23     d.sub.2                                                                         = 4.77                                                           r.sub.3                                                                         = 88     d.sub.3                                                                         = 2.0   nd.sub.2                                                                         = 1.79668                                                                           νd.sub.2                                                                      = 45.4                                   L.sub.2                                                                           r.sub.4                                                                         = 29.92  d.sub.4                                                                         = 4.0                                                            r.sub.5                                                                         = 75.6   d.sub.5                                                                         = 2.0   nd.sub.3                                                                         = 1.79668                                                                           νd.sub.3                                                                      = 45.4                                   L.sub.3                                                                           r.sub.6                                                                         = 42.07  d.sub.6                                                                         = 6.15                                                           r.sub.7                                                                         = 44.887 d.sub.7                                                                         = 3.8   nd.sub.4                                                                         = 1.72825                                                                           νd.sub.4                                                                      = 28.3                                   L.sub.4                                                                           r.sub.8                                                                         = -847.428                                                                             d.sub.8                                                                         = l (variable)                                                   r.sub.9                                                                         = 69.2   d.sub.9                                                                         = 1.8   nd.sub.5                                                                         = 1.62374                                                                           νd.sub.5                                                                      47                                       L.sub.5                                                                           r.sub.10                                                                        = -92.85 d.sub.10                                                                        = 3.0                                                            r.sub.11                                                                        = 32.09  d.sub.11                                                                        = 4.5   nd.sub.6                                                                         = 1.62374                                                                           νd.sub.6                                                                      = 47                                     L.sub.6                                                                           r.sub.12                                                                        = -26.167                                                                              d.sub.12                                                                        = 1.0   nd.sub.7                                                                         = 1.79668                                                                           νd.sub.7                                                                      = 45.4                                       r.sub.13                                                                        = 49.053 d.sub.13                                                                        = 0.1                                                            r.sub.14                                                                        = 22.072 d.sub.14                                                                        = 8.532 nd.sub.8                                                                         = 1.54739                                                                           νd.sub.8                                                                      = 53.6                                   L.sub.7                                                                           r.sub.16                                                                        = -93.3  d.sub.16                                                                        = 2.0                                                            r.sub.17                                                                        = -40.965                                                                              d.sub.17                                                                        = 1.5   nd.sub.10                                                                        = 1.80518                                                                           νd.sub.10                                                                     = 25.5                                   L.sub.8                                                                           r.sub.18                                                                        = 22.941 d.sub.18                                                                        = 2.0                                                            r.sub.19                                                                        = -4438.92                                                                             d.sub.19                                                                        = 4.0   nd.sub.11                                                                        = 1.50137                                                                           νd.sub.11                                                                     = 56.5                                   L.sub.9                                                                           r.sub.20                                                                        = -19.604                                                                              d.sub.20                                                                        = 0.4                                                            r.sub.21                                                                        = 13256.965                                                                            d.sub.21                                                                        = 2.1   nd.sub.12                                                                        = 1.51823                                                                           νd.sub.12                                                                     = 59                                     L.sub.10                                                                          r.sub.22                                                                        = -39.89                                                                __________________________________________________________________________             l = 22.582 ˜ 0.6                                                        First surface (r.sub.1) non spherical                                         K = 1, C.sub.2 = 0                                                            C.sub.4 = 0.6062 × 10.sup.-5 C.sub.6 = -0.3366 ×                  10.sup.-8                                                                     C.sub.8 = 0.2327 × 10.sup.-11 C.sub.10 = -0.4809 ×                10.sup.-16                                                                    f.sub.11 = -38.34 = 1.097fΛ                                   __________________________________________________________________________